High voltage circuit breakers are used in the transmission and distribution of three phase electrical energy. The circuit breakers operate to physically separate current-carrying contacts in each of the three phases by opening the circuit to prevent the continued flow of current in response to a sensor or protective relay fault or other system disturbance detection on the protected circuit. The circuit breakers include interrupters, which function to open and close current carrying contacts, interrupter operating mechanisms and linkages, arcing control mechanisms and interrupting media, one or more tanks for housing the interrupters, and bushings, which carry the high voltage electrical energy from the protected circuit into and out of the tank(s) (in a dead tank breaker).
The tanks in which the circuit breakers are housed are typically filled with an inert gas, such as, e.g., SF6, which acts as an insulator to control arcing. An electrical arc, which is the result of a circuit breaker opening or closing, can develop across the switch contacts especially the closer the contacts are to closure. The inert gas is preferably maintained at a predetermined density to ensure that the inert gas insulates as designed. Due to possible leaks or system malfunctions, the density of the inert gas must be constantly monitored.
In conventional gas monitoring systems, gas from each of the tanks in a multi-tank circuit breaker system, is typically fed back to a single density monitoring device. If the density falls to an insufficient level, this design makes it difficult to determine which tank is actually experiencing the leak. In addition, the intricate piping system typically needed creates more places for leaks to occur.
In other gas monitoring systems, a gas monitoring device is installed in the vessel wall of each of the tanks. Although individual tank monitoring is enabled, such systems tend to require temperature compensation systems or complex mounting arrangements due to space constraints and suffer from reduced accuracy.
Thus, it is desirable to provide improved systems and methods that facilitate gas density monitoring.